Liquid crystal display devices (LCDs), including in-plane switching (IPS) and fringe field switching (FFS) LCD modes, are common and used in a variety of display applications. In such devices, a liquid crystal (LC) layer is provided between two alignment layers that operate to align the LC molecules with a particular alignment, such as horizontal or vertical. The strength or stability of the alignment of the LC molecules may be characterized by the alignment or anchoring energy of the alignment layer applied to the LC molecules. To generate different light transmission from the LC layer, a voltage is applied to the electrode which generates an electric field which applies a force to the LC layer, which can overcome the anchoring or alignment energy of at least of portion of the LC molecules to re-align said LC molecules. When the voltage is removed, the LC molecules will relax (re-orient) back to the alignment dictated by the alignment layers, and the time for such relaxation (re-orientation) commonly is referred to as the off-time.
Attempts have been made to improve LCD operation by modification of the alignment layers. For example, JP 2017-211566 (Maeda et al., published Nov. 30, 2017) describes a display system in which the alignment layers are patterned in a manner whereby the anchoring energy above the electrodes is lower than the anchoring energy directly above the inter-electrode gaps. This is done to lower the operating voltage of the device. Increasing the anchoring energy above the inter-electrode gaps, however, can lead to a brightness reduction, as the re-alignment in response to the electrode voltage is reduced in the inter-electrode gaps due to a combination of; a smaller electric field magnitude in the inter electrode gaps as well as the higher anchoring energy at the inter-electrode gaps.
A similar effect of lowering the operating voltage can be achieved by using a uniform weak alignment layer, as disclosed in an article to Sato et al. (“An in-plane Switching Liquid Crystal Cell With Weakly Anchored Liquid Crystals On the Electrode Substrate” Journal of Materials Chemistry C, 2017.5.4384-4387). However, while this configuration can increase the brightness and decrease the operating voltage, the on and off switching times to re-orient the LC molecules of the display upon application and removal of the voltage are increased, which reduces the overall performance of the display system.
Other adjustments to alignment layers have been used to improve aspects of display performance. For example, U.S. Pat. No. 5,953,091 (Jones et al., issued Sep. 14, 1999) discloses a display system in which the alignment direction of an LCD is patterned to induce a multi-domain pixel. U.S. Pat. No. 5,861,931 (Gillian et al., issued Jan. 19, 1999) discloses a display system in which the alignment direction of an alignment layer is patterned in a manner to induce different director orientations in an LC layer to create a patterned polarization rotator. Such configurations do not relate to improving brightness issues whiling maintain effective switching times.